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Commit 578b016f authored by Kent Yoder's avatar Kent Yoder
Browse files

hw_random: add support for the TPM chip as a hardware RNG source 



This driver will make use of any available TPM chip on the system as a
hwrng source.

Acked-by: default avatarDavid Safford <safford@linux.vnet.ibm.com>
Signed-off-by: default avatarKent Yoder <key@linux.vnet.ibm.com>
parent 41ab999c

drivers/char/hw_random/Kconfig

+13 −0
Original line number Diff line number Diff line
@@ -289,3 +289,16 @@ config HW_RANDOM_EXYNOS 
	  module will be called exynos-rng.



	  If unsure, say Y.



config HW_RANDOM_TPM

	tristate "TPM HW Random Number Generator support"

	depends on HW_RANDOM && TCG_TPM

	default HW_RANDOM

	---help---

	  This driver provides kernel-side support for the Random Number

	  Generator in the Trusted Platform Module



	  To compile this driver as a module, choose M here: the

	  module will be called tpm-rng.



	  If unsure, say Y.

drivers/char/hw_random/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -25,3 +25,4 @@ obj-$(CONFIG_HW_RANDOM_PICOXCELL) += picoxcell-rng.o 
obj-$(CONFIG_HW_RANDOM_PPC4XX) += ppc4xx-rng.o

obj-$(CONFIG_HW_RANDOM_PSERIES) += pseries-rng.o

obj-$(CONFIG_HW_RANDOM_EXYNOS)	+= exynos-rng.o

obj-$(CONFIG_HW_RANDOM_TPM) += tpm-rng.o

drivers/char/hw_random/tpm-rng.c

0 → 100644
+50 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2012 Kent Yoder IBM Corporation

 *

 * HWRNG interfaces to pull RNG data from a TPM

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA

 */



#include <linux/module.h>

#include <linux/hw_random.h>

#include <linux/tpm.h>



#define MODULE_NAME "tpm-rng"



static int tpm_rng_read(struct hwrng *rng, void *data, size_t max, bool wait)

{

	return tpm_get_random(TPM_ANY_NUM, data, max);

}



static struct hwrng tpm_rng = {

	.name = MODULE_NAME,

	.read = tpm_rng_read,

};



static int __init rng_init(void)

{

	return hwrng_register(&tpm_rng);

}

module_init(rng_init);



static void __exit rng_exit(void)

{

	hwrng_unregister(&tpm_rng);

}

module_exit(rng_exit);



MODULE_LICENSE("GPL v2");

MODULE_AUTHOR("Kent Yoder <key@linux.vnet.ibm.com>");

MODULE_DESCRIPTION("RNG driver for TPM devices");